#SMD REFLOW OVEN HOW TO#

Solder: These are the metal particles that after melting will join the leads of a component to their corresponding pads on the circuit board. It also helps the soldering process by promoting the wetting of the molten solder, and protects the metal surfaces from re-oxidation during soldering. With its unique make up, solder paste performs three different and important functions during the solder reflow process:Īdhesive: The sticky nature of the paste holds the surface mount parts in place until the solder reflows to form a permanent bond.įlux: This is a chemical cleaning agent that prepares the metal surfaces before soldering by removing oxides and impurities. Solder paste is a mixture of metal solder particles and sticky flux which has the consistency of paste.

We’ve already mentioned how solder paste is used to hold the components onto the board as it goes through the solder reflow oven, but it actually does much more than just that. Reflow: The board now is heated again to melt, or reflows the solder.Ĭooling: The board now goes through a controlled cooling cycle to solidify the newly formed solder joints.Ĭlose up view of soldered components on a circuit board This will activate the flux in the solder paste in order to remove the oxides on the metal soldering surfaces. Soak: Once the board reaches the first designated temperature, it will remain here for a predetermined period. Preheat: This brings the board up to its first designated temperature. The solder reflow process generally follows this pattern: As the board travels through the oven on a conveyor belt, the duration spent in these different zones is also controlled by the thermal profile. These zones are individually regulated for precise temperatures according to a user-controlled thermal profile that is pre-programmed into it. With the components now installed in their correct locations, the circuit board is then run through the solder reflow oven.Īn industrial solder reflow oven uses multiple heat zones for the soldering process.

We’ll talk more about solder paste and how it works a little bit later. Next the components are installed on those pads, and the solder paste will hold them in position until they are firmly soldered in place.

The solder reflow process first starts with applying solder paste to all of the surface mount pads on the board. The most widely used method of soldering components for mass production, however, is the solder reflow process, which is used primarily to solder surface mount components to the circuit board. PCB assemblers will use wave soldering systems for mass production of boards or automated selective soldering processes for specific applications. First, there’s the traditional method of hand soldering them, where a technician uses a soldering iron and works on each connection separately. Introduction to the Solder Reflow OvenĮlectronic components can be soldered onto a printed circuit board in a couple of different ways. Let’s look at how the solder reflow oven is used for this process, and what you as a designer need to know to make sure that the process runs smoothly. This process completes the assembly of the board by melting the solder to form good solid solder joints between the components and the board. Using a combination of radiated heat and heat convection, the solder reflow oven delivers a carefully regulated flow of consistent heat to the PCB.

The industrial ovens used to reflow solder on a printed circuit board are intricate tools.

#SMD REFLOW OVEN HOW TO#

When the oven is an industrial version used to reflow PCB solder, it’s even more important to know how to use it. That’s because an oven produces a lot of heat, and if used carelessly will create a disaster. You’ve probably seen the same scenes smoke rolling out of the oven, disappointed family members ordering a pizza, and nothing left but blackened cinders where there should have been a magnificent turkey, ham, casserole, or dessert. One of the more common themes I’ve noticed in holiday movies is the unfortunate person who destroys dinner in the oven.

Smd reflow oven